Accession Number : ADA137902

Title :   Barriers to the Migration of Interphase Boundaries.

Descriptive Note : Final rept. 3 Oct 79-8 Sep 83,

Corporate Author : CARNEGIE-MELLON UNIV PITTSBURGH PA

Personal Author(s) : Aaronson,H I ; Reynolds,W T , Jr ; Chattopadhyay,K ; Shiflet,G J

PDF Url : ADA137902

Report Date : 06 Jan 1984

Pagination or Media Count : 141

Abstract : The incomplete transformation phenomenon was shown to be absent in Fe-C-Mo alloys containing 0.15 - 0.25% C and 2 1/4 - 4 1/2% Mo. Four different types of thickening kinetics of grain boundary allotriomorphs were observed in the temperature region at and just above that of the bay in the TTT-diagram. Close to the bay in the richest alloys, growth was found to cease entirely for preceptible intervals. Cessation of growth for sufficiently long times was identified as an essential element for the occurrence of incomplete transformation. Radical changes in ferrite and carbide morphology were catalogued in and below the bay region in a representative Fe-C-Mo alloy. The solute drag-like effect appears to be the primary factor responsible for incomplete transformation, for the complex growth kinetics observed in the present alloys and for the morphological effects in the bay region. Evolution of the interphase boundary structure of alpha sub1 Cu-Zn plates was studied with high-resolution TEM.

Descriptors :   *Grain boundaries, *Phase transformations, *Iron alloys, *Carbon alloys, *Molybdenum alloys, Grain structures(Metallurgy), Barriers, Migration, Ferrites, Carbides, Phase diagrams, Nucleation, Growth(General), Solutes, Drag, Bainite, Martensite, Crystal lattices, Shear properties, Dislocations, Reaction kinetics, Thickness, Interfaces

Subject Categories : Physical Chemistry
      Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE